A Nuclear HIDA (gallbladder) scan is a test that is done to evaluate gallbladder function. It can detect blockage in the tubes (bile ducts) that lead from the liver to the gallbladder and small intestine (duodenum). During a nuclear HIDA scan, a radioactive tracer substance is injected into a vein in the arm. The liver removes the tracer from the bloodstream and adds it to the bile that normally flows through the bile ducts to the gallbladder. The gallbladder then releases the tracer into the beginning of the small intestine. The scanning pictures are taken as the tracer moves through the liver, bile ducts, gallbladder, and duodenum.

Why It Is Done

A nuclear HIDA scan is done to:

• Help determine the cause of pain in the upper right side of the abdomen.
• Evaluate the function of the gallbladder. A gallbladder ultrasound may be done before a nuclear HIDA scan to help detect structural problems in the gallbladder. If the ultrasound is normal, a nuclear HIDA scan often is done to evaluate gallbladder function.
• Help determine the cause of jaundice.
• Detect blockage of the tubes (bile ducts) leading from the liver to the gallbladder and small intestine (duodenum).

How To Prepare

Before your nuclear HIDA scan, tell your doctor if:

• You are or might be pregnant.
• You are breast-feeding. Use formula (discard your breast milk) for 1 to 2 days after the scan until the radioactive tracer has been eliminated from your body.
• Within the past 4 days, you have had an X-ray test using barium contrast material (such as a barium enema) or have taken a medication (such as Pepto-Bismol) that contains bismuth. Barium and bismuth can interfere with test results.

Do not eat for 4 hours before having a nuclear HIDA scan.

How It Is Done

A nuclear HIDA scan is usually done by a nuclear medicine technologist. The scan pictures are usually interpreted by a radiologist or nuclear medicine specialist.

You will need to remove any jewelry that might interfere with the scan. You may need to take off all or most of your clothes, depending on which area is being examined (you may be allowed to keep on your underwear if it does not interfere with the test). You will be given a cloth or paper covering to use during the test.

The technologist cleans the site on your arm where the radioactive tracer will be injected. A small amount of the radioactive tracer is then injected.

You will lie on your back on a table and a large scanning camera will be positioned closely above your abdomen. After the radioactive tracer is injected, the camera will scan for radiation released by the tracer and produce pictures as the tracer passes through your liver and into your gallbladder and small intestine. The first pictures will be taken immediately after the injection, and then about every 5 to 10 minutes for up to the next 1½ hours. Each scan takes only a few minutes. You need to lie very still during each scan to avoid blurring the pictures. The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done.

A substance (cholecystokinin) that stimulates the gallbladder may also be injected into your vein during the scans. The pictures taken after this injection can help determine whether the gallbladder is functioning normally. Computer analysis of the data may be used to evaluate gallbladder function. You may be asked to answer questions about your reaction to the cholecystokinin. Occasionally medication (morphine sulfate) is given to help diagnose inflammation of the gallbladder.

Depending upon your results, additional scans may be taken up to a day later. If you need to return for another nuclear HIDA scan, you should not eat any fatty foods before you return.

The nuclear HIDA scan takes about 1 to 2 hours.

How It Feels

You may feel nothing at all from the needle puncture when the tracer is injected, or you may feel a brief sting or pinch as the needle goes through the skin. Otherwise, a nuclear HIDA scan is usually painless. You may find it difficult to remain still during the scan. Ask for a pillow or blanket to make yourself as comfortable as possible before the scan begins.

The test may be uncomfortable if you are having abdominal pain. Try to relax by breathing slowly and deeply.

If cholecystokinin is used during the test, it may cause nausea or abdominal pain. The development of these symptoms during the test may indicate a problem with your gallbladder. The technologist may ask you about changes in your pain during the test.

Risks

Allergic reactions to the radioactive tracer are rare. Most of the tracer will be eliminated from your body (through your urine or stool) within a day, so be sure to promptly flush the toilet and thoroughly wash your hands with soap and water. The amount of radiation is so small that it is not a risk for people to come in contact with you following the test.

Occasionally, some soreness or swelling may develop at the injection site. These symptoms can usually be relieved by applying moist, warm compresses to your arm.

There is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the low level of radiation released by the radioactive tracer used for this test.

Results

A nuclear HIDA scan is a nuclear scanning test that is done to evaluate gallbladder function. The results of a nuclear HIDA scan are usually available within 2 days.